Process of preparing dispersions of coal and oil



June 13, M39. s. KIESSKALT tr AL A 2,162,200

PROCESS OF PREPARING DISPERSIONS OF COAL AND OIL Filed May 18, 1956Patented June 13, 1939 amazon PROCESS OF me DISPEBSIONS or AND 01LSiegfried Kiesskalt, Hans Tampke,

nacker, and Ernst Weingaertner,

Karl Win- Frankforton-the-Main, Germany, assignors to I. G.Farbenindustrie Aktiengesellschatt, Frankforton-the-Main, GermanyApplication May 1a, 1936, Serial No. 80,440

In Germany 13 Claims.

The present invention relates to a process of preparing dispersionsof-coal and oil.

We have found that flowing coal poor in ash and in some cases even freefrom ash can be a made in one operation in the following manner:

Coal is ground in water in any desired grinding apparatus, for instancein a tube mill oran oscillating device, and in the form of a thickviscous paste is kneaded with oil in a kneading l0. apparatus so as toform a coherent, plastic mass. During this kneading operation the watercontained in the paste of coal first separates almost completely and maybe drawn ofi. Simultane ously a considerable portion of the ash'isremoved together with the water. By a subsequent washing operationduring the kneading this ash {removal can be enhanced. By adding the oilby degrees (in 2 to 3 portions) and simultaneously washing with water,it is possible to diminish the g0 ash content of the paste of coal toabout 0.5 per cent. During the entire operation the plastic condition ofthe dispersion of coal and oil is maintained.

During the grinding with water the hydrophile 5 gangue is thoroughlybroken up and wetted.

During the kneading of the very viscous paste an intensive mixing of thewater phase and the oil phase is produced by the shearing force of thekneading movement, and the ash' together L 80 with the water iseliminated from the dispersion of coal andoil.

By the name "Trent process there is known a process according to whichcoal groundin water-is made into a paste with oil and an excess as ofwater and then further treated with a relatively small quantity of oilin a flotation device. During thistreatment the coal particles 'wettedwith oil float upwards and are then drawn of! in the form of anon-coherent mass. This process 40 has the drawback that it requiresdisproportiom ately large quantities of water and, in consequence',large dressing devices. In contradistinction thereto the present processhas the advantage that it is possible to obtain a complete re- 45 movalof ash with a considerably smaller addition of water by the kneadingwith water together with oil. I

The separation may be hastened and the extent of the ash removal and thedesiccation may 50 be increased-by adding, according to the character ofthe coal and the oil, a small proportion of an acid or a base. Forinstance, the ash removal 'from, and desiccation of, lignite, with theuse of lignite tar oils, may be favored by the addition 55 of acids as,for instance, hydrochloric acid, su1- water content does not exceed 35per cent. It

May 24, 1935 furic acid, acetic acid, oleic acid and phenols. It

may be understood, however, that lignite may' be treated also with otheroils by adding acids. On the other hand the ash removal from anddesiccation of, coal by means of coal tar oil is .5 considerablyacceleratedby the presence of a small quantity of a base, for instance,caustic soda solution, caustic potash solution and aniline. The acid orbase maybe added to the aqueous paste before or during the kneading orto the oil.- v

We have furthermore found that some kinds of lignite can yield adispersion of coal and oil which flows well and can be conveyed with theusual pump devices byusing a paste'of coal and water which has been madewith a coal having'a content of water or not more-than about 35 percent.

In this case it is immaterial whether there is used a coal in the wetstate in which it comes from the mine and already containing in thisstate not more, than about 35 per cent. of water, or a coal which haspreviously been dried until its f is surprising that the flowing powerof a paste prepared with the aid of a coal of this kind is maintainedeven in cases in which the walls [subsequently made by addition of waterinto a ;paste of a suitable and increased content of water in order toobtaima mass capable of bein kneaded. I

It may be particularly advantageous to use roller mills as kneadingapparatus for carrying out this process. Whereas, in general, in thetreatment in roller mills pigments or fllli smaterials are rolled intoviscous, plastic masses, for instancedyestuilsinto linseed oil varnishor soot '5 into caoutchouc, it has been observed that in some cases alsoseparating effects can be obtained in roller mills, this beingsurprising. In a system consisting of coal containing ash, oil and waterobtained by an intensive mixing, water 40 and ash may, for instance, beseparated by treating the mixture in a roller mill. During thistreatment it is noted that when the mixture enters the pass between therollers, by the action of the shearing force 01 the intake movement,first the water is squeezed outwards from the mixture and then the ashconstituents are elimihated with the water.

The drawing diagrammatically shows a device with a roller mill, whichdevice is suitable for the inlet 3 oil is added thereto. The mixture is.as

conveyed by the transporting worm to the rollers t and 5 which are veryclosely adjusted. In the centre above the two rollers a sump 6 is formedwherein the mixture of coal, oil and water is 5 treated. By the rotationof the rollers the paste is moved in the direction indicated by arrows.

A small quantity of the paste is continuously pressed from the sump 6between the rollers and forms at the under ports ofthe rollers a thin 10fllm I and 8 the weight of which is about 1 of the mass in the sump 8.During the going through between the rollers the main quantity of thewater contained in the paste is removed and drops to the bottom 9. Thefllms I and 8 are loosened from the rollers by scrapers II and H andfall over slide plates l2 and it into suitable containers.

The advantage of using roller mills for this process is that on the one.hand the .operation may be continuous with a considerably lowerconsumption of power than, for instance, in a. Werner-Pfleidererkneading apparatus. On the other hand, by the action of the shearingforce on the highly viscous paste the particles of coal 2 are morefinely crushed so that further particles of ash are dissociated from thecoal and eliminated. It, follows that an additional quantity of ash maythus be separated from the paste from which with the aidot kneadingand-watering so in the Werner-Pfleiderer kneading apparatus ash can nolonger be separated. The kneading process which according to theproperties of the coal lasts only a few minutes may be considerablyaccelerated by an addition which increases the tendency for the coal tobe wetted by oil and reduces the tendency for it to be wetted by water,such as tetrahydronaphthalene, benzene,-aniline and alcohols of highmolecular weight. The separation of water '40 caused by the kneadingprocess may be improved by the application of a temperature of about40C. to- 100 0., and if required, by the application of a reducedpressure. The grinding operation in the aqueous phase as preceding thekneading operation affords an opportunity for a simultaneous chemicaltreatment, such as desulfurization, removal of iron and the like.

The process may be applied for the manufacture of flowing coal, and alsofor the manufacture of dust coal poor in ash in which case the oil,suitably of low boiling point,- present in the paste is evaporated. Bythis method it is also possible to make dispersions of graphite inlubricating oils, such as are used for lubricating movable engine parts.For this purpose there are suitable not only graphite but alsoanthracite, coal. lignite, coke and semi-coke, but particular- I!wastecoal rich in ash as obtained in the go washeries oi the coaldressings.

In comparison with the hitherto usual method for the manufacture offlowing coal, the process has, apart from the quality of the productsobtained, the advantage that-it is posibie to apply 55 the wet grindingprocess for the manufacture of flowing coal free from or poor in ash,whereby there isattained, in comparison with the dry grinding process, aconsiderable savingof energy with an improved output of fineness.

In comparison with the known flotation process the process ofthepresent'invention is distinguished by the fact that in the plasticvphases there is required only a fraction of the water which must be usedin these known processes.

The following examples serve to illustrate the equal weight of water.

amaaoo water and most of the ash separate. A dispersion of coal and oilis produced containing only 1 per cent. of ash.

(2) A coal having an ash content of 8.3 per cent. is treated asdescribed in Example 1. The dispersion of coal and oil of 50 per cent.strength which is produced shows an ash content of only 1 per cent.

(3) parts of a lignite coke containing 19.2 per cent. of ash is finelyground with 100 parts of water for about 15 hours in an oscillatingdevice such as that described in U. S. patent ap-. piication Serial No.731,172, flied June 18, 1934, in the name of Siegfried Kiesskalt andWalther Meier. The aqueous paste so obtained is then kneaded in aWerHer-Pfleiderer kneading apparatus with 100 parts of a mineral oil.Together with the separation of the water most of the ash separates andis eliminated by elutriation with water. There is obtained a dispersionof coke and oil containing 4.1 per cent. of ash.

(4) 100 parts of a dry coal having an ash content of 14.4 per cent. and50 parts of water are made into a paste in a known kneading apparatus.After the addition of 100 parts of crude oil, 40 parts of water togetherwith most of the ash separate within a few minutes. The separa-- tion ofash is completed by subsequently rinsing with about to 200 parts ofwater, while con tinuously kneading. About 210 parts of a paste of coaland oilare producedcontaining only 1 per cent. of ash and 5 per cent. ofwater.

(5) A lignite containing 12.8 per cent. of ash and in the wet state inwhich it comes from the mine is ground in a suitable grinding device. Ina known kneading machine, for instance in a Werner-Pfleiderer kneadingapparatus, the ground coal is flrst mixed with water and made into apaste and subsequently kneaded with an equal weight of a lignite taroil, calculated upon the dry coal, while adding 1 per cent. of sulfuricacid. After some minutes the water and most of the ash separate. Thereis produced a dispersion of coal and oil containing only 1 per cent. ofash.

(6) A coal containing 7.3 per cent. of ash is flnely ground in anoscillating device with an In a Werner-Pfleiderer kneading machine thecoal is kneaded in the form of an aqueous paste with an equalweight ofcoal tar oil, calculated 'upon the dry coal, while adding 0.5 per cent.of caustic soda solution of 40 B. After some minutes the water and mostof the ash separate. The dispersion of coal and oil of 50 per cent.strength produced has an ash content of 0.9 per cent.

(7) A coal containing 11.8 per cent. of ash is flnely ground with anequal quantity of water in a suitafle grinding apparatus. The coal iskneaded in a Werner-Pfleiderer kneading apparatus in the form of anaqueous paste with two thirds. of its weight (calculated upon the drycoal) of coal tar oil, with the addition .of 0.2 per cent. of causticsoda solution of 100 per cent. strength. After a short time most of thewater together with the ash can be .separated. The dispersion of coaland oil, thus already freed from ash to a large extent, is then furtherkneaded in a Werner-Pfleiderer kneading apparatus in the presence ofwater and together with 2 per cent.

of sulfuric acid calculated upon the weight of (8-) 100 parts of agroundlignite in the wet state in which it comes from the mine and cona largepart of ash are separated.

taining 55 per cent. of .water and 12.7 per cent. of ash, calculatedupon anhydrous lignite, are kneaded together with 18 parts of water soas to form a paste. On addition of 2 per cent. of sulfuric acid,calculated upon the dry lignite, and 45 parts of lignite tar oil, about45 parts of water and 15 parts of water are added to the paste of lignite and oil and kneading is continued. By kneading with this smallquantity of water .the residual ash is separated from the paste orlignite and oil and may be removed with the water. This procedure isrepeated four times more, using 15 parts of water each time. After thefive treatments, the removal of ash hasproceededto such an extent thaton further kneading the paste with water the supernatant rinsing waterremains clear. The paste of lignite and oil which is produced has an ashcontent of only 1 per cent. and a water content of about 20 per cent.that is to say, the water content of the lignite in the ,wet state as itcomes from the mine has been reduced by about 50 per cent.

'(9) 156 parts of a lignite in the. wet state in which it comes from themine and containing 55 dry lignite, are made into'a paste in a suitablekneading apparatus together with 44 parts of water and 5.3 parts ofhydrochloric acid of 100 per cent. strength, and the paste is kneadedwith about 63 parts of a lignite tar. After a short time about '70 partsof water separate, together with most-of the ash. By kneading in thepresence of further 100 to 150 parts of water the separation of ash isfinished. The dispersion of lignite and oil which is produced containsabout 1 per cent. of ash and can be readily formed into briquettes inthe known briquetting plants.

A coal containing 11.6 per cent. of ash is finely ground in anoscillating device with about an equal weight ofwater. The aqueous pasteof coal isomixed in a suitable mixing apparatus with about an equalweight of coal taroil, calculated upon dry coal, while adding 0.5 percent. of caustic soda solution of 40 B.,'likewise calculated upon drycoal. The mixture is then introduced 6 times successively into atworoller mill during which operation the water and most of the ashseparate. The dispersion of coal and oil obtained, of 50 per cent.strength, has an ash content of'only 1 per cent. o

(11) 150 parts of an aqueous coal paste which consists of 60 parts of.water and 90 parts of ground dry coal having an ash content of; 11.5per cent. are kneaded in a roller mill together with 0.5 per cent. ofcaustic soda solution, calculated upon the anhydrous coal and '70 partsof a coal tar oil. After the paste has passed through the rollersseveral times, about 54 parts ofwater and most of the ash separate fromthe hydrous, spongy mixture of coal and oil. The separation of ash iscompleted by subsequently rinsing with a small quantity of water. lnorder to obtain a dispersion of coal and oil which is easily conveyedfurther 10 parts of coal tar oil are rolled into the mixture. There isobtained a dispersion of coal and'oil containing 1 per cent. of ash andabout-3 per cent. of water. i

(12) 128 parts of an aqueous paste of lignite consisting of 100 parts ofground lignite in the wet state inwhich it.comes from the mine and'having a water content of 55 per cent., 28 parts a paste of coal and oilwhich has a water content of,8 percent. and an ash-content of about 1per cent.

(13) 156 parts of a salt-containing crude lignite having a watercontent, of 50 per cent. and' corresponding to 70 parts of dry ligniteare previ-' ously dried by waste heat to produce 120 parts of lignitehaving a water content of 35 per cent.

"The lignite is then made into a paste in a'suitable kneadingdevicetogether with 47 parts of water and 5.85 parts of hydrochloricacid of 100 .per cent. strength (7.5 per cent. calculated upon drylignite) and the paste is kneaded with 44 parts or lignite hydrogenationoil. Aftera short time About 45 parts of water phase reversal occurs. Iand most of the ash separate. By kneading in the presence-of further 100parts of water the separation of ash is completed. The paste of coal.per cent. of water, corresponding to 70 parts of plastic condition to asqueezing and shearing ac-- tion for a suflicient time toreplace thewater by the oil and materially reduce the ash content oi! the coal andremoving the ash and water which separate.- I s 2. Process of preparingdispersions of coal and oil which comprises-subjecting a paste of coaland water with about an equal quantity of 011 calculated upon the drycoal, while continuously maintaining the plastic condition-to asqueezingand shearing action for asufllcient time to replace the water by the oiland materially reduce the ash content of the coal and removing the ashand water which separate.

' 3. Process 01' preparingv dispersions of coal and oil whichcomprises'kneading 'a paste of coal and water with oil by means-of aroller mill wherein the oil is added'by degrees while continuously.maintaining the plastic condition for a suflicient time to replace thewater by the oil and materially reduce the ash content ofthe coal andremoving the ash and water which separate.

4. Process of preparing dispersions of coal and oil which compriseskneading a paste of coal and water with about an equal quantity of oil,calcalated updn the dry. coal, by means 01 a roller mill wherein the oilis added by degrees while continuously maintaining the plastic conditionfor a 7 6. Process of preparing dispersions of coal and oilwhich'comprises subjecting a paste of lignite in the wet state in whichit comes from the mine and water with oil while continuously maintainingthe plastic condition to a squeezing and shearing action for asufllcienttime to replace the water by the oil and materially reduce theash content of the coal and removing the ash and water I which separate.

7. Process of preparing dispersions of coal and oil which comprisessubjecting a paste of coal and water with oil while continuouslymaintaining the plastic condition to a squeezing and shearing action fora suflicient time to replace the water by the oil and materially reducethe ash content of the coal, washing the dispersion with water duringthe kneading process and removing the ash and. water which separate.

8. Process of preparing dispersions of coal and oil which compriseskneading a paste of coal and water with about an equal 'quantity of oil,calculated upon the dry coal, by means of a roller mill wherein the oilis added by degrees while continuously maintaining the plastic conditionfor a suflicient time to replace the water by the oil and materiallyreduce the ash content of the coal washing the dispersion with waterduring the kneading process and removing the ash and water whichseparate.

9. Process of preparing dispersions of coal and oil which comprisessubjecting a paste of coal and water containing a small quantity of anacid with oil while continuously maintaining the plastic condition toasqueezing and shearingaction for a suflicient time to replace the waterby the oil and materially reduce the ash content or the coal andremoving the ash and water which separate.

10. Process of preparing dispersions of coal and oil which compriseskneading a paste of coal and water, containing a small quantity of anacid, with oil by means of a roller mill wherein the oil is added bydegrees while continuously maintaining the plastic condition for asumcient time to replace the water by the oil and materially reduce theash content of the coal and removing the ash and water which separate. I

11. Process of preparing dispersions of coal and oil which comprisessubjecting a paste of coal and water, containing a small quantity of abase, with coal tar oil while continuously maintaining the plasticcondition to a squeezing and shearing action for a suflicient time toreplace the water by the oil and materially reduce the ash content ofthe coal and removing the ash and water which separate. I

12. Process of preparing dispersions of coal and oil which compriseskneading a paste of coal and water, containing a small quantity of abase, with coal tar oil by means of a roller mill wherein the oil isadded by degrees while continuously maintaining the plastic conditionfor a sufllcient time to replace the water by the oil and materiallyreduce the ash content of the coal and removing the ash and water whichseparate.

13. Process of preparing dispersions of 'lig'nite and oil whichcomprises kneading by means of a roller mill a paste of lignite andwater with about an equal quantity of oil, calculated upon the drylignite, said paste containing a small quantity of hydrochloric acidwhile continuously maintaining the plastic condition for a sufllcienttime to re place the water by the oil and materially reduce the ashcontent of the coal, washing the dispersion with water during thekneading process and removing the ash and water which separate.

SIEGFRIED KIESSKALT. HANS TAMPKE.

KARL WINNACKER. ERNST WERNGAER'I'NER.

